How can I detect double click events in matplotlib?

问题

import matplotlib.pyplot as plt

def onclick(event):
    print event.button

fig = plt.figure()
connection_id = fig.canvas.mpl_connect('button_press_event', onclick)
plt.show()

With a construct like this, I have the problem of double-clicks hitting onclick() handler three times. I guess that it is receiving both the clicks, and an additional double-click event. How can I change this behaviour so that the event handler is not fired for double-click events? Or, alternatively, how can I detect them from the event instance so that I can ignore those double-clicks?

note: button_release_event does not have this problem, but I want to fire on the button_press_event

回答1:

When i had matplotlib version 1.1rc, i was not able to catch dblclick event. Later, I wrote code for matplotlib 1.2 and that is ok

import matplotlib.pyplot as plt
fig = plt.figure()
def onclick(event):
    if event.dblclick:
         print event.button

connection_id = fig.canvas.mpl_connect('button_press_event', onclick)
plt.show()

回答2:

I was able to detect the case by using

from gtk.gdk import BUTTON_PRESS, _2BUTTON_PRESS. _3BUTTON_PRESS

note: the reason for underscores on double and triple click enum types is not that they are _protected, but to dodge the issue where you aren't allowed to have an attribute starting with a number. You can check the event type with:

event.guiEvent.type

However, I later found out that the import will cause an exception if you are using a different backend (moreover, I only have this problem with 'GTKAgg' backend). So now I use a construct like this:

from gtk.gdk import BUTTON_PRESS as singleclick

if plt.get_backend() == 'GTKAgg':
    if hasattr(event, 'guiEvent') and event.guiEvent.type != singleclick:
        # suppress double click event
        return

If anyone has a cleaner solution, feel free to add it here.

回答3:

I had encountered the same problem when I was using matplotlib 1.1. There was no 'dblclick' event type. So I implemented it by myself. I required the time interval between two clicks must be smaller than 0.5 sec or the program would do nothing. User could tune this setting by itself according to its experience.

import matplotlib.pyplot as plt
import time

fig = plt.figure()
one_click_trigger = False
time_first_click  = 0

def mouseDoubleClick(event):
    global one_click_trigger
    global time_first_click

    if one_click_trigger == False:
        one_click_trigger = True
        time_first_click = time.time()
        return
    else:
        double_click_interval = time.time() - time_first_click
        if double_click_interval > 0.5:
            one_click_trigger = False
            time_first_click = 0
            return

    print "Double click!"

fig.canvas.mpl_connect('button_press_event', mouseDoubleClick)
plt.show()

来源：https://stackoverflow.com/questions/6703242/how-can-i-detect-double-click-events-in-matplotlib

标签

python

events

double-click

matplotlib